[CALCITE-6236] EnumerableBatchNestedLoopJoin::estimateRowCount return…

…s wrong value

core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableBatchNestedLoopJoin.java

@@ -34,6 +34,7 @@
 import org.apache.calcite.rel.core.Join;
 import org.apache.calcite.rel.core.JoinRelType;
 import org.apache.calcite.rel.metadata.RelMdCollation;
+import org.apache.calcite.rel.metadata.RelMdUtil;
 import org.apache.calcite.rel.metadata.RelMetadataQuery;
 import org.apache.calcite.rex.RexNode;
 import org.apache.calcite.util.BuiltInMethod;
@@ -55,6 +56,7 @@
 public class EnumerableBatchNestedLoopJoin extends Join implements EnumerableRel {
 
   private final ImmutableBitSet requiredColumns;
+  private final double rightSideFilterSelectivity;
   protected EnumerableBatchNestedLoopJoin(
       RelOptCluster cluster,
       RelTraitSet traits,
@@ -63,9 +65,11 @@ protected EnumerableBatchNestedLoopJoin(
       RexNode condition,
       Set<CorrelationId> variablesSet,
       ImmutableBitSet requiredColumns,
-      JoinRelType joinType) {
+      JoinRelType joinType,
+      double rightSideFilterSelectivity) {
     super(cluster, traits, ImmutableList.of(), left, right, condition, variablesSet, joinType);
     this.requiredColumns = requiredColumns;
+    this.rightSideFilterSelectivity = rightSideFilterSelectivity;
   }
 
   public static EnumerableBatchNestedLoopJoin create(
@@ -74,7 +78,8 @@ public static EnumerableBatchNestedLoopJoin create(
       RexNode condition,
       ImmutableBitSet requiredColumns,
       Set<CorrelationId> variablesSet,
-      JoinRelType joinType) {
+      JoinRelType joinType,
+      double rightSideFilterSelectivity) {
     final RelOptCluster cluster = left.getCluster();
     final RelMetadataQuery mq = cluster.getMetadataQuery();
     final RelTraitSet traitSet =
@@ -89,7 +94,19 @@ public static EnumerableBatchNestedLoopJoin create(
         condition,
         variablesSet,
         requiredColumns,
-        joinType);
+        joinType,
+        rightSideFilterSelectivity);
+  }
+
+  @Deprecated
+  public static EnumerableBatchNestedLoopJoin create(
+      RelNode left,
+      RelNode right,
+      RexNode condition,
+      ImmutableBitSet requiredColumns,
+      Set<CorrelationId> variablesSet,
+      JoinRelType joinType) {
+    return create(left, right, condition, requiredColumns, variablesSet, joinType, 1.0);
   }
 
   @Override public @Nullable Pair<RelTraitSet, List<RelTraitSet>> passThroughTraits(
@@ -115,14 +132,14 @@ public static EnumerableBatchNestedLoopJoin create(
   @Override public EnumerableBatchNestedLoopJoin copy(RelTraitSet traitSet,
       RexNode condition, RelNode left, RelNode right, JoinRelType joinType,
       boolean semiJoinDone) {
-    return new EnumerableBatchNestedLoopJoin(getCluster(), traitSet,
-        left, right, condition, variablesSet, requiredColumns, joinType);
+    return new EnumerableBatchNestedLoopJoin(getCluster(), traitSet, left, right, condition,
+        variablesSet, requiredColumns, joinType, rightSideFilterSelectivity);
   }
 
   @Override public @Nullable RelOptCost computeSelfCost(
       final RelOptPlanner planner,
       final RelMetadataQuery mq) {
-    double rowCount = mq.getRowCount(this);
+    double rowCount = estimateRowCount(mq);
 
     final double rightRowCount = right.estimateRowCount(mq);
     final double leftRowCount = left.estimateRowCount(mq);
@@ -144,6 +161,18 @@ public static EnumerableBatchNestedLoopJoin create(
         rowCount + leftRowCount, 0, 0).plus(rescanCost);
   }
 
+  @Override public double estimateRowCount(RelMetadataQuery mq) {
+    return unwrapDouble(RelMdUtil.getJoinRowCount(mq, this, condition,
+            unwrapDouble(mq.getRowCount(getRight())) / rightSideFilterSelectivity));
+  }
+
+  static double unwrapDouble(Double value) {
+    if (value == null) {
+      return Double.POSITIVE_INFINITY;
+    }
+    return value.doubleValue();
+  }
+
   @Override public RelWriter explainTerms(RelWriter pw) {
     super.explainTerms(pw);
     return pw.item("batchSize", variablesSet.size());

core/src/main/java/org/apache/calcite/adapter/enumerable/EnumerableBatchNestedLoopJoinRule.java

@@ -40,6 +40,8 @@
 import java.util.List;
 import java.util.Set;
 
+import static org.apache.calcite.adapter.enumerable.EnumerableBatchNestedLoopJoin.unwrapDouble;
+
 /** Rule to convert a {@link LogicalJoin} to an {@link EnumerableBatchNestedLoopJoin}.
  * You may provide a custom config to convert other nodes that extend {@link Join}.
  *
@@ -134,9 +136,14 @@ public EnumerableBatchNestedLoopJoinRule(RelBuilderFactory relBuilderFactory,
       conditionList.add(condition2);
     }
 
+    RexNode filterCondition = relBuilder.or(conditionList);
+
     // Push a filter with batchSize disjunctions
-    relBuilder.push(join.getRight()).filter(relBuilder.or(conditionList));
+    relBuilder.push(join.getRight()).filter(filterCondition);
     final RelNode right = relBuilder.build();
+    final double filterSelectivity =  right.getInputs().size() == 1
+        ? unwrapDouble(call.getMetadataQuery().getSelectivity(right.getInput(0), filterCondition))
+        : 1.0;
 
     call.transformTo(
         EnumerableBatchNestedLoopJoin.create(
@@ -147,7 +154,8 @@ public EnumerableBatchNestedLoopJoinRule(RelBuilderFactory relBuilderFactory,
             join.getCondition(),
             requiredColumns.build(),
             correlationIds,
-            join.getJoinType()));
+            join.getJoinType(),
+            filterSelectivity));
   }
 
   /** Rule configuration. */

core/src/main/java/org/apache/calcite/rel/metadata/RelMdUtil.java

@@ -796,6 +796,12 @@ public static double getMinusRowCount(RelMetadataQuery mq, Minus minus) {
   /** Returns an estimate of the number of rows returned by a {@link Join}. */
   public static @Nullable Double getJoinRowCount(RelMetadataQuery mq, Join join,
       RexNode condition) {
+    return getJoinRowCount(mq, join, condition, mq.getRowCount(join.getRight()));
+  }
+
+  /** Returns an estimate of the number of rows returned by a {@link Join}. */
+  public static @Nullable Double getJoinRowCount(RelMetadataQuery mq, Join join,
+      RexNode condition, Double rightRowCount) {
     if (!join.getJoinType().projectsRight()) {
       // Create a RexNode representing the selectivity of the
       // semijoin filter and pass it to getSelectivity
@@ -813,7 +819,7 @@ public static double getMinusRowCount(RelMetadataQuery mq, Minus minus) {
     // Row count estimates of 0 will be rounded up to 1.
     // So, use maxRowCount where the product is very small.
     final Double left = mq.getRowCount(join.getLeft());
-    final Double right = mq.getRowCount(join.getRight());
+    final Double right = rightRowCount;
     if (left == null || right == null) {
       return null;
     }

core/src/test/java/org/apache/calcite/test/enumerable/EnumerableBatchNestedLoopJoinTest.java

@@ -226,6 +226,7 @@ class EnumerableBatchNestedLoopJoinTest {
             + "join locations l on e.empid <> l.empid and d.deptno = l.empid")
         .withHook(Hook.PLANNER, (Consumer<RelOptPlanner>) planner -> {
           planner.removeRule(EnumerableRules.ENUMERABLE_CORRELATE_RULE);
+          planner.removeRule(EnumerableRules.ENUMERABLE_JOIN_RULE);
           // Use a small batch size, otherwise we will run into Janino's
           // "InternalCompilerException: Code of method grows beyond 64 KB".
           planner.addRule(